1. Field of the Invention
This invention relates to an image presentation device for presenting an image by means of a computer, and particularly to an image presentation device which produces and presents an animation according to an interactive operation by a user.
2. Description of the Related Art
Systems which present an animation by an interactive operation using computer graphics (hereinafter referred to as CG) are known for various uses. For example, there is a system which generates three-dimensional CG images and moves a visual point and objects upon the input operation by a user, thereby presenting a walk-through animation where a visual point can be moved within a building. Another system shows on a display previously produced two-dimensional animation components and interactively presents a two-dimensional animation upon operations by a user with a mouse.
In such interactive animations, to switch the motion of an object on the scene according to the operations by the user, or to switch the presented state of an object on the scene by switching between display and non-display, multiple scene data, which contain the motions of appearing objects and the execution and non-execution of display, are previously provided as data described for each presented state, and these scene data are switched when the interactive animation is executed. And, scenario data, which describe the procedures for execution while successively switching the scene data and the alternatives for scene switching, are generated to execute the presentation of an animation.
These conventional types of image presentation device for presenting an interactive animation need to have scene data for each presented state when a scene has a plurality of presented states. Therefore, to designate the motion information of appearing objects common to individual scene data and to change the display and non-display, the designating and display changing operations are required to be repeated for all the plurality of scene data. And, they have a disadvantage that setting of a condition branch for the plurality of data is complicated. Consequently, there are disadvantages that significant labor is required for managing and editing the scenario data as the number of presented states increases, and productivity is lowered.
Furthermore, the conventional image presentation devices use scene data, in which presentation states are previously described, to present an animation and cannot change the scene data while executing. Thus, it is disadvantageous that a user cannot generate and execute a scene as he or she desires while executing the scenario and scenes cannot be developed freely.
The conventional image presentation devices describe a scenario for executing the motions in a large virtual space or a long scenario for successively executing short partial stories according to the progress of a story as a single large-scale and complicated scenario data. Therefore, switching information on the motion in a large space and switching of the motions according to the progress of a story are required to be described in single and complicated large-scale data for each appearing object, resulting in the increase of labors required for making a scenario.
It is also disadvantageous that a scenario cannot be made by two or more scenario creators because the scenario data is one.